The invention relates to butterfly valves and a particular object of the invention is to provide a butterfly valve device for connecting and isolating conduits providing a good seal despite a simple arrangement enabling easy manufacture in a version that can be motorized and can include a plurality of channels.
Butterfly valves introduce only a small head loss and constitute balanced systems. They are of benefit in automobile vehicle cooling circuits, in which pumps of relatively low power (100 watts to 200 watts) could then be used; furthermore, these valves could easily be actuated by motors such as steeper motors. However, an application of this kind in the thermostatic art requires an excellent seal, which makes it difficult to use such valves at present.
The object of the invention is to remedy this drawback and to this end the invention provides a device for connecting and isolating fluid conduits, the device including a casing incorporating at least one fluid passage discharging from the casing via ports adapted to be connected to the conduits and containing at least one butterfly valve fixed to a spindle which can pivot about its longitudinal axis, characterized in that the casing includes two casing members having respective joint surfaces which are pressed together in at least one joint plane crossing the passage transversely and passing through the axis of the spindle, and the joint surfaces each include a cavity enlarging the passage all around its perimeter and in which a packing is housed, the two packings facing each other across the passage and being pressed together in the joint plane to constitute a sealing ring which incorporates two aligned holes in which two regions of the spindle on respective opposite sides of the butterfly valve are mounted to pivot in sealed contact all around their perimeter, and each packing has a first inside wall portion between the holes on one side of the passage with dimensions adapted to enable the butterfly valve to pivot on this side from a fully open position in which it is approximately longitudinal in the passage to an approximately transverse closed position, and a second internal wall portion between the holes on the other side of the passage and having dimensions adapted to prevent access to the closed position from that side, the first internal wall portion of each packing being adjacent the second portion of the other packing, each second portion projecting farther into the passage than the adjacent first portion over at least part of the length of the packing to define a face extending transversely to the perimeter of the passage, from one hole of the sealing ring to the other, forming a seat for the butterfly valve, the faces of the two packings forming seats facing in opposite directions.
Thanks to the above design, the two packings provide a seal between the two regions of the fluid flow passage on respective opposite sides of the butterfly valve in the closed position, a seal between the passage and the exterior and a seal for the spindle carrying the butterfly valve.
The device can further have one or more of the following features:
on respective opposite sides of the butterfly valve the spindle is accommodated in housings provided for it in the two casing members and the joint surface of at least one of the two members incorporates grooves on respective opposite sides of the passage, in the form of loops surrounding the housing at a distance and discharging into the cavity for the packing of the member, and sealing loops in one piece with the packing are accommodated in the grooves,
it includes at least two passages in the casing in each of which there is a butterfly valve,
the passages discharge to the exterior of the casing via ports one of which is common to those passages, which open into each other on the same side as that port,
the butterfly valves are fixed to the same spindle and are in perpendicular planes so that one is fully open when the other is closed,
around each passage, the joint surfaces of the two casing members each have a cavity enlarging the passage all around its perimeter and in which a packing is accommodated, the two packings around each passage being pressed together at the joint plane to constitute a sealing ring with aligned holes through it in which two regions of the spindle are mounted to pivot in sealed contact all around their perimeter, the two packings each having a face forming a set for the butterfly valve, the faces of the two packings forming seats facing in opposite directions,
the same spindle carries the two butterfly valves and extends in the casing on respective opposite sides of and between the two butterfly valves in housings in which it is supported by rings, and the joint surface of at least one of the two casing members incorporates grooves between the cavities surrounding the passages and in respective loops on either side of the passages at a distance around the housings, and said grooves accommodate connecting branches of the packings and the sealing loops in one piece with the packings,
it includes a motor fixed to the exterior of a casing member, the spindle is extended on one side of a passage and projects into a chamber of the casing into which an output shaft of the motor also projects, and the output shaft is connected to the spindle by connecting means so that rotation of the shaft drives rotation of the spindle,
it includes motor-drive means consisting of a wax expansion thermostat and the spindle is extended on one side of a passage, projects into a chamber of the casing into which a mobile rod associated with the thermostat also projects, and the mobile rod is connected to the spindle by connecting means so that movement in translation of the mobile rod drives rotation of the spindle,
one of the grooves surrounds at a distance a combination formed by the chamber and a housing for the spindle and a sealing loop in one piece with a packing is housed in said groove.